relocating bathroom & wc

Hi there,

I'm sorry if this is a bit long, but I'm hoping that I'm making myself reasonable clear.

I'm trying to recover my 3rd bedroom (back bedroom), which is currently the bathroom/wc (victorian end-of-terrace 3 up/3down)

Don't particularly want to revert to the original design of outside wc and a tin bath in the kitchen, although I guess that would be 'real restoration'

Anyhow, I figure that by jiggering around with the layout of the 'middle' bedroom and the corridor from stairs to 'back' bedroom I can actually get 1 'ensuite' bathroom/wc for the main 'front' bedroom (about 1900*1400 mm) and 1 'family' bathroom/wc (about 2500*140 mm)

I reckon that the longest conceivable run of foulwater pipework would be 8800 mm (8.8 metre) in a straight line to the outside of the back wall, with 90degree turn and further 2000mm (2 metre) run to the soil stack.

The back bedroom floor is 150 mm lower than the rest of the house

looking at the bldg reg approved document 'H' seems I would need for bath/shower 40 mm pipe for washbasin 32 mm pipe for WC 100 mm pipe

as far as I can tell I need to allow 18mm fall per metre length for all

3 items so for the (worst case) 8.8 metre run I would need to allow a drop of 159 mm

Now, I plan to raise the level of the back bedroom floor to the same level as the corridor, So I *think* I can generate a big enough fall. (possibly, perhaps, maybe hedge hedge caveat caveat)

But then further on in the 'document H' section H1 diagram 3 it seems to suggest the following max run for 32 mm pipe = 1.7 metre max run for 40 mm pipe = 3.0 metre max run for 100 mm pipe = 6.0 metre for a single WC (but in table 2 above the diagram it suggests that I could have a 15metre run if more than 1 WC discharging into same pipe)

So at this point I get confused. Seems like the 'cleanish' foulwater has to be generated closer to the soil stack than the 'nasty' foulwater.

What am I reading rong please!

Cheers & thanks for listening

Che